[Usenet; poss.: fr.: DEC slang for a full
software distribution, as opposed to a patch or upgrade] A source software
distribution that has been packaged in such a way that it can
(theoretically) be unpacked and installed according to a series of steps
using only standard Unix tools, and entirely documented by some reasonable
chain of references from the top-level README file.
The more general term distribution may imply that
special tools or more stringent conditions on the host environment are
required.